Proteomics has emerged as a key discipline in the post-genomic 'tool chest' and over the last few years, proteomics technology has become extraordinarily powerful. Mass spectrometry, array based protein methods and single cell imaging methods have combined to give us rich data of all the expressed proteins of the cell, 'its proteome'. While the technology is still developing rapidly, and 'data collection' efforts are just gathering steam, the focus of this meeting will be on applications of proteomics to problem solving in molecular cell biology as well as in molecular medicine. Bioinformatics methods to keep track of the wealth of data and beginning efforts to integrate disparate large-scale data sets will also be highlighted. Another emerging area in bioinformatics and systems biology is the building of models of whole cells. The rapid growth of proteomics, the present pressing need for the development of standards and protocols for the experimental methods and data interpretation, and the necessity for facile communication among investigators having disparate backgrounds (e.g., biology, medicine, biochemistry, bioinformatics, instrumentation) makes the Keystone format ideal for the timely exchange of information in a setting where there is ample opportunity for discussions within small groups and between individuals. Students and postdoctoral fellows will be able to present their work and to make connections with leading investigators, thus increasing their own exposure and forging connections that can generate career opportunities in rapidly expanding fields where there is high demand for well-trained, creative researchers.